In a rigid, hinged-lid packet of cigarettes, the group of cigarettes is wrapped in a sheet of foil inner packing material, on which no glue is applied; a sheet of rigid outer packing material, to which glue is applied, is folded about the sheet of inner packing material; and the sheet of outer packing material is wrapped in a waterproof overwrapping comprising a sheet of transparent plastic packing material, which is heat sealed.
The sheet of foil inner packing material is always in the form of an elongated rectangle, and is first folded into a U about the group of cigarettes; depending on the design of the packing machine used to produce the packet of cigarettes, the sheet of inner packing material may first be folded into a U about the group of cigarettes either crosswise or longitudinally with respect to the cigarettes.
One example of folding a sheet of packing material about a group of cigarettes is described in Patent GB 785076.
The sheet of foil inner packing material has a tear-off top portion defined by a tear-off line, and which, when the packet of cigarettes is first opened, is torn off to permit easy access to the cigarettes. The tear-off line defining the tear-off top portion is normally straight, and is formed on a packing machine by means of a special rotary cutter.
When the lid only covers a lateral portion of the packet (as described, for example, in U.S. Pat. No. 5,957,280) and the sheet of inner packing material is first folded into a U about the group of cigarettes longitudinally with respect to the cigarettes, the tear-off line defining the tear-off top portion may be so complicated in shape as to be difficult to produce on the machine.